Oh, what a delightful little puzzle you have there! Let's see... how about the word "treasure"? It has eight letters, and the third letter is indeed an 'r.' Keep exploring the beauty of words, my friend!
caripace
garbage
Some six letter words with the second letter R and the third letter I are:arisesbribedbridalbridgebridlebrightcringecrisiscrispycriticdrippydriveldriverfridgefriendfrightfrigidfrillyfringefriskyfrizzygrievegrillegrinchgrittyorientoriginoriolepriestprimalprimerprinceprisonprivettribaltrickytrifletripletripodtrivettriviaurinalwriterwrithe
The only 8 letter word you can get out of CESERCNT is crescent
perfect?
territory
through
Perfected is a synonym for finished. The third letter is an r.
preserve
cobbler
blurryblurtschurchchurnsflurryfourthhourlymournspouredscurryslurpssouredspurnssturdytoured
certain